Electrochemical Polymerization of Aniline Monomers Infiltrated into Well-Ordered Truncated Eggshell Structures of Polyelectrolyte Multilayers

Abstract

The use of nanosphere lithography to construct two-dimensional arrays of polystyrene (PS) particles coated with multilayered polyelectrolyte (PE) shells and truncated eggshell structures composed of PE thin layers is reported. The truncated eggshell PE structures were produced by extraction of the PS particle cores with toluene. The core-extraction process ruptures the apex of the PE coating and causes a slight expansion of the PE thin layers. Aniline hydrochloride was infiltrated into the PE shells and subsequently electropolymerized to yield an array of a composite containing polyaniline (PAni) and PE thin shells. Voltammetric, quartz crystal microbalance, and reflectance Fourier transform infrared spectroscopic measurements indicate that aniline monomers were confined within the thin PE shells and the electropolymerization occurred in the interior of the PE shell. The PE thickness governs the amount of infiltrated monomer and the ultimate loading of the PAni in the truncated eggshell structure. Surface-structure imaging by atomic force microscopy and scanning electron microscopy, carried out after each step of the fabrication process, shows the influence of the PE thickness on the organization and dimensions of the arrays. Thus, the PE thin shells composed of different layers can function as nanometer-sized vessels for the entrapment of charged species for further construction of composite materials and surface modifications. This approach affords a new avenue for the synthesis of new materials that combine the unique properties of conductive polymers and the controllability of template-directed surface reactions.

Form and Function in Multilayer Assembly: New Applications at the Nanoscale

“…a) SEM image of a monolayer of hexagonally close-packed polystyrene particles coated with two polyelectrolyte bilayers (atomic force microscopy (AFM) image in inset). b) A topographical AFM image of truncated hollow multilayer shell structures after the extraction of the PS cores with toluene (reproduced from [183], with permission: copyright 2004, the American Chemical Society).…”

“…Zhou and co-workers have reported the formation of unique ªtruncated eggshellº structures that are formed through the assembly of an hexagonal monolayer of polystyrene microparticles coated with polyelectrolyte multilayers, followed by the dissolution of polystyrene to form a regular array of concave circular collapsed capsules. [183] The capsules are exposed to a solution of aniline monomer; the positively charged aniline adsorbed to the negatively charged top surfaces of the capsules, and penetrated the interiors of the capsule walls. After rinsing all excess, unbound monomer away, the monomer is electropolymerized within the arrays to create a polyaniline coated truncated sphere array, as shown in Figure 13.…”

Conducting Polymers in Sensor Design

“…Briseno et al also reported [24] truncated eggshell structures of the polyelectrolyte to template the PANI growth.…”

Polyelectrolytes: Influence on Evaporative Self-Assembly of Particles and Assembly of Multilayers with Polymers, Nanoparticles and Carbon Nanotubes

“…An interesting method for deposition is that based on self-assembly, particularly by controlled evaporation [77]. Two-dimensional arrays of polystyrene particles (600 nm) coated with polyelectrolytes were presented [78], while ordered arrays of microcapsules in solution can be harnessed to propagate chemical signals in directed and controllable ways, allowing signals to be transmitted over macroscopic distances [79]. Therefore, it is desirable to investigate the influence of polyelectrolyte multilayer coatings on 3D self-assembly of colloidal particles because such materials are of interest for photonic crystal ordering, free-standing structures, membranes and sensors and self-assembled structures in general.…”